Various types of rod gripping and driving jaws have heretofore been used in an effort to exert a sufficient gripping force on the installation rod to force the rod through the ground preporatory to installing a pipe or cable in the ground. Some of the rod gripping jaws heretofore used exerted radial inward pressure at points spaced somewhat longitudinally of the rod, and thus exerted a bending movement which would flex the rod to deflect the rod from its desired path and introduce destructive forces in the rod. Some of the gripping jaws heretofore used exerted spaced apart up and down or reversely spaced bending forces on the rods where it was contempleated that the forces would balance out over a short length of the rod, but such systems imposed undesirable loads on the rods which introduced internal destruction stresses, and caused the rods to bend.
In the use of an underground pipe installing device it is customary that the pipe installer be placed in an operating trench. To minimize the necessity for digging up the ground it is desirable that the pipe installing mechanism be as narrow as possible to avoid digging a wide operating trench which would disrupt the ground to an undesirable degree. The rod gripping jaws and jaw actuating mechanisms heretofore employed have been relatively wide, and therefore have necessitated the use of wide operating trenches to receive the apparatus required to exert sufficient force to drive the operating rod through the ground.